Recording medium, reproduction device, program, and reproduction method

ABSTRACT

Video streams and an entry map are recorded on a BD-ROM in association with each other. The video stream constituting a slide show includes a plurality of IDR pictures. The entry map (EP_map) associated with the IDR pictures indicates an entry time (PTS_EP_start) of each IDR picture included in the video stream in association with an entry point (SPN_EP_start). Application_type indicates that entry information of each of pieces of picture data constituting the video stream exists in the EP_map and each piece of picture data is to be decoded independently. When a time-based slideshow has been identified all of the pieces of picture data are repeatedly pointed to by entries in the entry map.

RELATED APPLICATIONS

This is a Divisional Application of the U.S. patent application Ser. No.11/579,223 filed Nov. 29, 2007 which is the U.S. National Phase of PCTApplication No. PCT/JP2005/010145 filed on Feb. 6, 2006.

TECHNICAL FIELD

The present invention relates to the field of a random access technique.

BACKGROUND ART

A random access technique is a technique for converting a point on atime line of a digital stream to a recording position on the digitalstream, and starting playback of the digital stream from the recordingposition. This is an essential technical basis for playing back digitalstreams recorded on a recording medium, such as a BD-ROM or a DVD-Video.

Digital streams are coded by a variable-length encoding method, such asMPEG2-Video or MPEG4-AVC, and the amount of information included in eachframe is different. Therefore, to perform the above-described conversionfor the random access, it is necessary to refer to an entry map. Theentry map indicates a plurality of entry times on a time line of adigital stream in one-to-one correspondence with a plurality of entrypoints on the digital stream. If the time accuracy of the plurality ofentry times on the entry map is one second, it is possible toefficiently perform the random access in time accuracy of one second.

For the random access targeting a video stream, it is necessary tosearch for an I (Intra) picture positioned at the beginning of a GOP. Adata structure supporting the search for the I picture is disclosed by aprior art below:

Patent Document 1: JP Patent Application Publication No. 2000-228656.

DISCLOSURE OF THE INVENTION

In addition to a movie application, a slide show also is an applicationthat uses a time line. A slide show is composed of a plurality of stillimages, each of which is played back along a previously defined timeline. Since the slide show also has a time line for playback, it ispossible to find a recording position on a stream based on a time pointon a time line and perform a playback from the recording position, byindicating a plurality of entry times in one-to-one correspondence withentry points.

However, since a slide show is composed of a plurality of still images,an accuracy required for the random access to the slide show is higherthan that to a movie. Here, the random access with a high accuracy is arandom access performed in units of pictures, e.g., accessing to thenext picture, to the picture ten pictures ahead, and so on. The timeaccuracy of the entry map for a video stream is approximately onesecond, and each of the intervals having a length of one second includestwenty to thirty pictures. Therefore, if realizing a high-accuracyrandom access performed in units of pictures by using theabove-described entry map, it is necessary to perform analysis of thestream in addition to the reference to the entry map.

Here, the “analysis of the stream” means the following processingprocedures: a picture header is extracted from an entry point describedin the entry map; a picture size is read from the header; the recordingposition of the next picture is specified based on the picture size; andthese procedures are repeated to reach to the recording position of thedesired picture. Such an analysis requires frequent accesses to thestream. Therefore, it takes considerably long time to read a pictureonly three or five pictures ahead of the entry point. Since it takes along time to perform the random access in units of pictures, there is aproblem that it is difficult for developers to add, to the slide show, afunction with satisfying usability of displaying, for example, theprevious picture or the next picture, or displaying a picture positionedten pictures ahead or behind.

The object of the present invention is to provide a recording mediumcapable of performing a high-speed random access in a slide show.

Means for Solving the Problem

To fulfill the above-described object, the present invention provides arecording medium having recorded thereon a video stream and streammanagement information, wherein the video stream includes a plurality ofpieces of picture data, the stream management information includes anentry map and a flag that indicates one of application types, the entrymap indicates an entry address of each piece of picture data incorrespondence with a playback start time thereof, the application typesinclude a movie and a time-based slideshow, and if a value indicatingthe time-based slideshow has been set to the flag, all the pieces ofpicture data are respectively pointed to by entries included in theentry map.

Advantageous Effects of the Present Invention

If a value indicating the time-based slideshow has been set to the flag,all the pieces of picture data are respectively pointed to by entriesincluded in the entry map. Therefore, it is possible to realize a randomaccess performed in units of pictures, e.g., accessing to the nextpicture, to the picture three pictures ahead, without analyzing thevideo stream.

The stream management information further includes a flag for indicatingthat entry addresses of all the pieces of picture data included in thevideo stream are pointed to by the entry map.

Even if the data structure of the entry map for the slide show isapparently the same as the data structure of the entry map for movingpictures, the playback device is required to perform the random accessin units of pictures only when the flag indicates the above, whileperforming playback control that is the same as that performed forplaying moving pictures. The playback device can realize the randomaccess performed in units of pictures with keeping the compatibilitywith playback of moving pictures. As a result, it is possible to promptthe use of playback devices having functions of playing back both movingpictures and a slide show.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a form of an act of using a recording mediumaccording to the present invention;

FIG. 2 is illustrates the internal structure of a BD-ROM;

FIG. 3 schematically illustrates the structure of a file with theextension “.m2ts”;

FIG. 4 illustrates the processes through which TS packets constitutingan AV Clip are recorded onto the BD-ROM;

FIG. 5A illustrates the internal structure of a video stream used forpresenting a movie;

FIG. 5B illustrates the internal structure of a video stream used forpresenting a slide show;

FIG. 6A illustrates the internal structure of an IDR picture, FIG. 6Billustrates the internal structure of a Non-IDR I picture and FIG. 6Cillustrates the dependency relationship between the Non-IDR I pictureand other pictures;

FIG. 7 illustrates the processes through which an IDR picture and aNon-IDR I picture are converted into TS packets;

FIG. 8 illustrates how the IDR pictures for a slide show are recorded onthe BD-ROM;

FIG. 9 illustrates progression of playback of a slide show;

FIG. 10 illustrates the internal structure of Clip information;

FIG. 11A illustrates Stream_Coding_Info of a video stream;

FIG. 11B illustrates Stream_Coding_Info of an audio stream;

FIG. 12 shows an internal structure of Clip info in the Clipinformation;

FIG. 13 illustrates the setting of an EP_map for a video stream carryinga movie;

FIG. 14 illustrates pairs of EP_Low and EP_High values representing thePTS_EP_start and the SPN_EP_start of entry points #1-#5 illustrated inFIG. 13;

FIG. 15 illustrates the processes through which a random access to thevideo stream illustrated in FIG. 13;

FIG. 16 illustrates the internal structure of EP_map set for a slideshow;

FIG. 17 illustrates a random access to a point of time on a time line,in the same manner as FIG. 16;

FIG. 18 illustrates the internal structure of a playback deviceaccording to the present invention;

FIG. 19 is a flowchart showing a processing procedure for convertingtime information to an I picture address with respect to a video streamused for presenting a movie;

FIG. 20 is a flowchart showing a processing procedure for convertingtime information to an Access Unit address with respect to a videostream used for presenting a slide show;

FIG. 21 illustrates the structure of PlayList information;

FIG. 22 illustrates a relation between AV Clip and PlayList information;

FIG. 23 illustrates the internal structure of each of a plurality ofpieces of PLMark information included n the PlayList informationaccording to the second embodiment;

FIG. 24 illustrates chapter definitions defined by PLMark information;

FIG. 25 illustrates a specific example of a setting of PLMark for avideo stream used for presenting a slide show;

FIG. 26 is a flowchart showing a chapter search processing procedure;

FIG. 27 is a flowchart showing a chapter skip processing procedure;

FIG. 28 illustrates the internal structure of AVClip according to thethird embodiment;

FIG. 29A illustrates the internal structure of an IG stream;

FIG. 29B shows an internal structure of an ICS;

FIG. 30 shows an exemplary ICS that defines interaction control in theslideshow;

FIGS. 31A to 31C show a menu that is displayed when a playback point ofa video stream reaches a point tx;

FIG. 32 shows a state transition in a menu displayed in the slideshow;and

FIG. 33 shows a branch resulting from a navigation command of theslideshow.

DESCRIPTION OF REFERENCE NUMERALS

-   -   1 BD Drive    -   2 Arrival Time Clock Counter    -   3 Source De-Packetizer    -   4 PID Filter 4    -   5 Transport Buffer 5    -   6 Multiplexed Buffer 6    -   7 Coded Picture Buffer 7    -   8 Video Decoder 8    -   10 Decoded Picture Buffer 10    -   11 Video Plane 11    -   12 Transport Buffer 12    -   13 Coded Data Buffer 13    -   14 Stream Graphics Processor 14    -   15 Object Buffer 15    -   16 Composition Buffer 16    -   17 Composition Controller 17    -   18 Presentation Graphics Plane 18    -   19 CLUT Unit 19    -   20 Transport Buffer 20    -   21 Coded Data Buffer 21    -   22 Stream Graphics Processor 22    -   23 Object Buffer 23    -   24 Composition Buffer 24    -   25 Composition Controller 25    -   26 Interactive Graphics Plane 26    -   27 CLUT Unit 27    -   28 Compositor 28    -   29 Compositor 29    -   30 Switch 30    -   31 Network Device 31    -   32 Local Storage 32    -   33 Arrival Time Clock Counter 33    -   34 Source De-Packetizer 34    -   35 PID Filter    -   36 Switch    -   37 Transport Buffer    -   38 Elementary Buffer    -   39 Audio Decoder    -   40 Transport Buffer    -   41 Buffer    -   42 Text Subtitle Decoder    -   43 Scenario Memory    -   44 Controller    -   46 PSR Set    -   100 BD-ROM    -   200 Playback Device    -   300 Remote Controller    -   400 television set

BEST MODE FOR CARRYING OUT THE INVENTION First Embodiment

The following describes an embodiment of a recording medium according tothe present invention. First of all, among various acts of practicing arecording medium of the present invention, an act of using is described.FIG. 1 illustrates a form of using the recording medium according to thepresent invention. In FIG. 1, a BD-ROM 100 is the recording mediumaccording to the present invention. The BD-ROM 100 is used to supply amovie to a home theater system composed of a playback device 200, aremote controller 300, and a television set 400. This concludes thedescription of the act of using the recording medium of the presentinvention.

Next, among various acts of practicing a recording medium of the presentinvention, an act of producing is described. The recording mediumaccording to the present invention can be put in practice by improvementof an application layer of the BD-ROM. FIG. 2 illustrates the internalstructure of the BD-ROM.

In the figure, the BD-ROM is illustrated on the fourth level, and thetrack of the BD-ROM is illustrated on the third level. In the figure,the track is laterally stretched out, although the track in practicespirals outwards from the center of the BD-ROM. The track is composed ofa lead-in area, a volume area, and a lead-out area. The volume area hasa layer model of a physical layer, a file system layer, and anapplication layer. The first level illustrates, in a directorystructure, a format of the application layer (application format) of theBD-ROM. As illustrated on the first level, the BD-ROM has a ROOTdirectory, and the ROOT directory has a BDMV directory.

The BDMV directory has three subdirectories called a PLAYLIST directory,a CLIPINF directory, and a STREAM directory.

The STREAM directory stores files with the extension “.m2ts” (e.g. filescalled 00001.m2ts, 00002.m2ts and 00003.m2ts) containing dataconstituting the main body of a digital stream.

The PLAYLIST subdirectory stores files with the extension “.mpls” (e.g.files called 00001.mpls, 00002.mpls and 00003.mpls).

The CLIPINF directory stores files with the extension “.clpi” (e.g.files called 00001.clpi, 00002.clpi and 00003.clpi).

<Structure of AV Clip>

The following describes files with the extension “.m2ts”. FIG. 3schematically illustrates the structure of a file with the extension“.m2ts”. Each file with the extension “.m2ts” (namely, 00001.m2ts,00002.m2ts, 00003.m2ts, . . . ) contains an AV Clip. The AV Clip(illustrated on the fourth level) is created as follows. A video streamcontaining a plurality of video frames (pictures pj1, pj2, pj3, . . . )and an audio stream containing a plurality of audio frames (bothillustrated on the first level) are separately converted to PES packets(illustrated on the second level), and further converted to TS packets(illustrated on the third level). These TS packets of the video andaudio streams are multiplexed to form the AV Clip.

Note that presentation graphics streams (PG streams) relating tosubtitles and interactive graphics streams (IG streams) relating tointeractions may also multiplexed to form the AV Clip. Further, subtitledata represented by text codes (text subtitle streams) may be recordedas the AV Clip.

Next, a description is given of how a AV Clip, which is a digital streamof the MPEG2-TS format, is recorded on the BD-ROM. FIG. 4 illustratesthe processes through which TS packets constituting the AV Clip arerecorded onto the BD-ROM. In FIG. 4, the TS packets of the AV Clip areillustrated on the first level.

As illustrated on the second level, “TS_extra_header” (denoted as “EX”in the figure) is attached to each TS packet of the AV Clip.

The third and fourth levels illustrate the physical units of the BD-ROMin relation to the TS packets. As illustrated on the fourth level, thetrack on the BD-ROM is divided into a plurality of sectors. The TSpackets with the TS_extra_header (hereinafter, simply “EX-TS packets”)are divided into groups of 32 EX-TS packets, and each group is writteninto three sectors of the BD-ROM. Each group composed of 32 EX-TSpackets amounts to 6,144 (=32×192) bytes, which is equal to the totalsize of three sectors (=2048×3). Each group of 32 EX-TS packets storedin three sectors of the BD-ROM is referred to as an “Aligned Unit”. Whendata is recorded onto the BD-ROM, encryption of data is carried out inAligned Units.

As illustrated on the fifth level, an error correction code is insertedevery 32 sectors to constitute an ECC block. As long as accessing theBD-ROM in Aligned Units, a playback device is ensured to obtain acomplete set of 32 EX-TS packets without missing any part. Thiscompletes the description of the processes of recording the AV Clip ontothe BD-ROM.

<Video Stream>

The following describes the internal structure of a video stream. FIG. 5illustrates the internal structure of a video stream. There are twotypes of video streams. One is a video stream used for presenting amovie, and the other is a video stream used for presenting a slide show.In this embodiment, the video streams of both types are commonly codedby MPEG4-AVC coding. In other words, they are common in the viewpoint ofthe coding method.

FIG. 5A illustrates the internal structure of a video stream used forpresenting a movie. The video stream illustrated in FIG. 5A is composedof a plurality of pictures aligned in the order of coding.

In the figure, the reference numerals “I”, “P”, and “B” denote an Ipicture, B picture, and P picture, respectively. There are two types ofI pictures, one is an IDR picture and the other is a Non-IDR I picture.Non-IDR I pictures, P pictures, and B pictures are coded usingcorrelation with other pictures. More specifically, a B picture iscomposed of Bidirectioanlly Predictive (B) slices. A P picture iscomposed of Predictive (P) slices. There are two types of B pictures,one is a reference B picture, and the other is a nonreference B picture.

In FIG. 5A, a Non-IDR I picture is denoted as “I”, and an IDR picture isdenoted as “IDR”. The same denotations are used throughout the followingdescriptions. This concludes the description of the video stream usedfor presenting a movie.

Next, the following describes the internal structures of an IDR pictureand a Non-IDR I picture. FIG. 6A illustrates the internal structure ofan IDR picture. As illustrated in the figure, the IDR picture iscomposed of a plurality of Intra-type slices. FIG. 6B illustrates theinternal structure of a Non-IDR I picture. Different from the IDRpicture composed solely of Intra-type slices, the Non-IDR I picture iscomposed of slices of Intra-type, P-type, and B-type. FIG. 6Cillustrates the dependency relationship between the Non-IDR I pictureand other pictures. A Non-IDR I picture may be composed of B and Pslices and thus may have a dependency relationship with other pictures.

<Recording to BD-ROM>

Next, the following describes how IDR pictures and Non-IDR I picturesare converted into TS packets and recorded onto the BD-ROM. FIG. 7illustrates the processes through which an IDR or Non-IDR I picture isconverted into TS packets. In the figure, the first level illustrates anIDR or Non-IDR I picture. The second level illustrates an Access Unitstipulated according to MPEG4-AVC. A plurality of slices constitutingthe IDR or Non-IDR I picture is sequentially aligned. Then, AUD (AccessUnit Delimiter), SPS (Sequence Parameter Set), PPS (Picture ParameterSet), SEI (Supplemental Enhanced Information) are attached to the slicesequence. In this way, the picture slices are converted into an AccessUnit.

AUD, SPS, PPS, SEI, Access Unit mentioned above are information allstipulated according to MPEG4-AVC and described in various documents,such as “ITU-T Recommendation H.264”. For the details, such documentsshould be referenced. The point in this description is that AUD, SPS,PPS, and SEI need to be supplied to a playback device for allowingrandom access to the video stream.

The third level represents NAL units. AUD, SPS, PPS, SEI, and each sliceillustrated on the second level are each attached with a header so as tobe converted into separate NAL units. NAL units are units supported bythe Network Abstraction Layer (NAL) stipulated according to MPEG-4 AVCand described in various documents, such as “ITU-T RecommendationH.264”. For the details, such documents should be referenced. The pointin this description is that AUD, SPS, PPS, SED, and each slice areconverted into separate NAL units and manipulated independently in theNetwork Abstraction Layer.

As described above, a plurality of NAL units obtained by converting thesingle picture are further converted into PES packets illustrated on thefourth level. The PES packets are then converted into TS packets.Finally, the resulting TS packets are recorded onto the BD-ROM.

In order to play back one GOP, the decoder needs to be supplied with aNAL unit containing AUD, among NAL units constituting the first IDR orNon-IDR I picture in the GOP. That is, the NAL unit containing AUD isused as an index for decoding the IDR picture or Non-IDR I picture. Inthis embodiment, each NAL unit containing AUD is regarded as a point.For playback of the video stream, the playback device recognizes each ofsuch a point as an entry point for playback of a Non-IDR I picture andan IDR picture. Consequently, for implementation of random access to theAV Clip, it is extremely important for the playback device to recognizethe locations of AUDs of IDR pictures and Non-IDR I pictures. Thisconcludes the description of the structure of the MPEG-4AVC video streamused for presenting a movie.

<Slide Show>

The following describes the video stream used for presenting a slideshow. FIG. 5B illustrates the internal structure of the video streamused for presenting a slide show. As shown in this figure, the videostream used for presenting the slide show is composed of a plurality ofpieces of still image data. Each of these pieces of data is an IDRpicture. In other words, in the case of a slide show, the pictures aredecoded as IDR pictures so that each picture is independently decoded.

A video stream and an audio stream are multiplexed to form the slideshow according to the present invention. This slide show is a TimebasedSlideShow in which the pictures included in the video stream aresequentially played back along with the progression of playback of theaudio stream.

On the other hand, as a slide show to be recorded on a BD-ROM, there isanother type called a browsable SlideShow, in which the audio stream isnot multiplexed and the pictures are played back regardless of playbackof audio stream.

Since both a movie and a Timebased SlideShow have a time line, thefollowing describes only the case of a movie and a Timebased SlideShow.

The internal structure of the video stream constituting a slide show isdescribed here.

FIG. 8 illustrates how the IDR pictures for a slide show are recorded onthe BD-ROM. The recording onto the BD-ROM is the same as FIG. 7illustrates. That is to say, since each of the IDR pictures constitutingthe slide show is composed of a plurality of pieces of slice data, andeach piece of slice data is converted to a NAL unit and recorded on theBD-ROM in the same manner as IDR pictures of a movie. The differencefrom FIG. 7 is that an “End of Stream code” is attached to the lastpiece of the slice data constituting the picture. The End of Stream codeis a terminal code for instructing the playback device to freeze theoperation of the decoder (Display Frozen). The End of Stream code isconverted to one NAL unit, and then recorded on the BD-ROM.

The IDR pictures illustrated in FIG. 8 are sequentially provided to thedecoder, and accordingly the playback of the slide show progresses asFIG. 9 illustrates. FIG. 9 illustrates progression of playback of theslide show. The fourth level of this figure shows a TS packet string,the third level shows a PES packet string obtained by converting the TSpackets of the fourth level. The second level shows a time line of theslide show, and the first level shows the IDR pictures constituting theslide show. Each of the IDR pictures of the first level is displayed ata time indicated by the PTS in the PES packet of the third level. Sinceeach PES packet of the third level includes the End of Stream codeillustrated in FIG. 8, the playback device goes into a status where theoperation of the decoder is frozen (Display Frozen) after displaying theIDR picture at a time indicated by the PTS in the PES packet. ThisDisplay Frozen status continues until when the next IDR picture isdisplayed. The playback device sequentially plays back the IDR picturesby repeating display of the picture performed at the time indicated bythe PTS included in the PES packet and freezing of the operation of thedecoder indicated by the End of Stream code. This concludes thedescription of the progression of playback of the slide show.

<Clip Information>

Next, the following describes files with the extension “.clpi”. Eachfile with the extension “.clpi” (e.g. 00001.clpi, 00002.clpi,00003.clpi, . . . ) contains Clip information. Each piece of Clipinformation is management information of an individual AV Clip. FIG. 10illustrates the internal structure of a piece of Clip information. Asillustrated in the left block of the figure, the Clip information iscomposed of the following fields:

(i) “ClipInfo( )” storing the attributes of the AV clip file;

(ii) “Sequence Info( )” storing information related to the ATC sequenceand STC Sequence;

(iii) “Program Info( )” storing information related to the programsequence; and

(iv) “Characteristics Point Info (i.e., CPI( ))”.

Leader lines cu1 in the figure indicates that the structure of the i-thprogram sequence (Program Sequence(i)) is illustrated in greater detail.As indicated by the leader lines cu1, the Program Info associated withthe Program Sequence(i) is composed of the total number of Ns(i) pairsof Stream_PID and Stream_Coding_Info (in the figure, Stream_PID[i](0)and Stream_Coding_Info(i, 0)-Stream_PID[i](Ns(i)−1) andStream_Coding_Info(i, Ns(i)−1)).

The Stream_PID is a packet identifier of an individual packet carryingan elementary stream constituting the AV clip. The Stream_Coding_Infoindicates the coding standard used to encode the elementary stream.

FIG. 11A illustrates the Stream_Coding_Info associated with the videostream, whereas FIG. 11B illustrates Stream_Coding_Info associated withthe audio stream. The Stream_Coding_Info is composed of the followingfields: “stream_coding_type” indicating the coding method of the videostream is either MPEG4-AVC or MPEG2-Video; “video_format” indicating thevideo format is 480i, 576i, 480p, 1080i, 720p, or 1080p; “frame_rate”indicating the frame rate of the video stream is 23.976 Hz, 29.97 Hz, or59.94 Hz; and “aspect_ratio” indicating the aspect ratio of the picturesis 4:3 or 16:9.

FIG. 11B illustrates the Stream_Coding_Info associated with the audiostream. As illustrated in the figure, the Stream_Coding_Info associatedwith the audio stream is composed of the following fields:“stream_coding_type” indicating the coding type of the audio stream isLPCM, Dolby-AC3, or Dts; “audio_presentation_type” indicating thepresentation type of the audio stream is stereo channel, mono channel,or multi-channel; “sampling_frequency” indicating the sampling frequencyof the audio stream; and “audio_language” indicating a language code ofthe audio stream.

With reference to the Stream_Coding_Info, the playback apparatus isenabled to identify which of the elementary streams contained in an AVclip are MPEG4-AVC streams.

<CPI(EP_Map)>

Next, a description of CPI is given with reference to FIG. 10 again.Leader lines cu2 in the figure indicates that the structure of CPI isillustrated in greater detail. As illustrated in the leader lines cu2,the CPI is composed of a plurality of EP_map fields. Each EP_map iscomposed of Ne pieces of EP_map_for_one_stream_PID (namely,EP_map_for_one_stream_PID(0)-(Ne−1)). Each piece ofEP_map_for_one_stream_PID is an EP_map associated with one of elementarystreams contained in the AV clip. An EP_map is information indicatingentry points set on the associated elementary stream. An entry point iswhere the Access Unit Delimiter of an I picture is present. The EP_mapindicates the packet number of each entry point (SPN_EP_start) and thecorresponding entry time (PTS_EP_start). Leader lines cu3 in the figureindicates that the internal structure of EP_map_for_one_stream_PID isillustrated in greater detail.

As illustrated in the figure, the EP_map_for_one_stream_PID is composedof Nc pieces of EP_High (EP_High(0)-(Nc−1)) and Nf pieces of EP_Low(EP_Low(0)-(Nf−1)). Here, the EP_High holds the most significant bits ofthe SPN_EP_start and PTS_EP_start of an I picture. The EP_Low holds theleast significant bits of the SPN_EP_start and PTS_EP_start of the Ipicture.

Leader lines cu4 in the figure indicate that the internal structure ofthe EP_High is illustrated in greater detail. As illustrated in theleader lines cu4, EP_High(i) is composed of the following fields:“ref_to_EP_Low_id[i]” which is a reference value to the EP_Low;“PTS_EP_High[i]” indicating the most significant bits of the PTS for theI picture; and “SPN_EP_High[i]” indicating the most significant bits ofthe SPN for the I picture. Here, the reference numeral “i” denotes anidentifier uniquely identifying an arbitrary EP_High field.

Leader lines cu5 in the figure indicate that the EP_Low structure isillustrated in greater detail. As indicated by the leader lines cu5, theEP_Low is composed of the following fields: “is_angle_change_point(EP_Low_id)”; “I_end_position_offset (EP_Low_id)” indicating the size ofthe associated I picture; “PTS_EP_Low(EP_Low_id)” indicating the leastsignificant bits of the PTS of the associated I picture; and“SPN_EP_Low(EP_Low_id)” indicating the least significant bits of the SPNof the associated I picture. Here, the “EP_Low_id” denotes an identifieruniquely identifying an arbitrary EP_Low field.

The data structure of the EP_map as described above is basicallydisclosed, for example, in the above patent literature. Thus, no furtherdescription is given in this specification.

Next, Clip info included in the Clip information is described. FIG. 12illustrates the internal structure of the Clip info included in the Clipinformation. In the figure, leader lines ct1 indicates that thestructure of ClipInfo( ) is illustrated in greater detail. As indicatedby the leader lines ct1, the ClipInfo( ) is composed of the followingfields: “clip_stream_type” indicating the type of the digital stream;“application_type” indicating the type of an application that uses theAV Clip; “TS_recording_rate” indicating the recoding rate of the AVClip; and a “number_of_source_Packet” indicating the number of TSpackets that constitutes the AV Clip. “application_stream_type”indicates whether the AVClip corresponding to this Clip information is aTS for Movie Application, a TS for Timebased SlideShow, a TS forMainPath of the Browsable SlideShow, or a TS for SubPath of theBrowsable SlideShow. Specifically, if

a) application_type=1, the AVClip is a Movie Application;

b) application_type=2, the AVClip is a Timebased SlideShow;

c) application_type=3, the AVClip is a MainPath of the BrowsableSlideShow, where “MainPath” signifies that of the video stream—audiostream set that constitutes the Browsable SlideShow, the AVClip is thevideo stream; and

d) application_type=4, the AVClip is a SubPath of the BrowsableSlideShow, where “SubPath” signifies that of the video stream—audiostream set that constitutes the Browsable SlideShow, the AVClip is theaudio stream.

Arrows ct3 and ct4 illustrated in FIG. 12 indicate secondary meanings ofthe application_type, that is, the data structure of the EP_map thatchanges in accordance with the value of the application_type.

The arrow ct4 in this figure indicates that when the application_type is1 or 4, the interval between two consecutive values of the PTS_EP_startin the EP_map should be less than 1 second.

The arrow ct3 in this figure indicates the data structure of the EP_mapwhen the value of the application_type is 2 or 3. More specifically,when the application_type is 2 or 3, the value of the PTS_EP_startshould be set such that all the pictures included in the AV Clip arepointed. In other words, it is assured that all the pictures included inthe AV Clip are pointed by the EP_map.

The following describes technical significance of attaching suchsecondary meanings to the application_type.

Setting all the pieces of picture data to be IDR pictures to create aslide show is merely one of various ideas. It is possible to use Ppictures that have been coded with use of the relation to otherpictures, or use B pictures that are coded that have been coded with useof the relation to two or more pictures ahead and behind the picture, tostructure a video stream. Therefore, some authors might structure aslide show using P pictures and B pictures.

However, pictures to be referred to are necessary for decoding Ppictures and B pictures. Therefore, for playing an arbitrary pictureincluded in a slide show in accordance with a user's instruction, it isnecessary to decode closest reference pictures to decode the picture.

Accordingly, every time a desired picture is played back, all thepictures referred to by the desired picture are required to be decoded.Therefore, a slide show structured by P pictures and B pictures mighthave low usability.

In a slide show, not like playback of a movie, the order of the playbackof pictures is not sequential. In other words, it is necessary to playback a picture in accordance with a user's instruction. In thisembodiment, to ensure that the play back can be started from anypicture, the video stream used for presenting the slide show is composedof intra-coded IDR pictures each of which can be decoded independently.This means that the idea of constituting the slide show with P picturesand B pictures is expelled and all the pictures constituting the slideshow are encoded to IDR pictures.

Based on this structure of the slide show, the entry points and theentry times of all the pictures are described in the EP_map.Accordingly, any picture data that the user wishes to decode can beplayed back by as a still picture only providing the picture data to thedecoder.

Whether a video stream is used for presenting a slide show is indicatedby application_type in Clip_info. Whether the application_type indicatesa slide show has a secondary meaning, that is, whether the positions andthe playback start times of the pictures constituting a video stream areindicated by the EP_map.

Since the application_type in Clip_info has such meanings, the playbackdevice can know that each of the pictures constituting the video streamsis IDR picture and does not refer to any other picture and that all thepictures are indicated by the EP_map, by referring to the Clip_info inthe AV Clip to be played back.

As a result, to present the slide show, the playback device can decode adesired picture without decoding the previous and the next pictures.

This concludes the technical significance of the application_type andthe EP_map.

The following describes the difference between configurations of EP_mapfor a movie and EP_map for a slide show, by taking a specific example.FIG. 13 illustrates a configuration of EP_map for a video stream(application_type=1 or 4) of a movie. The first level indicates aplurality of pictures aligned in the order of display. The second levelindicates the time line of the pictures. The fourth level indicates TSpacket string on a BD-ROM, and the third level indicates theconfiguration of the EP_map.

On the time line of the second level, Access Units (Non-IRD pictures andIDR pictures) are located at time points t1 to t7. If the intervalsbetween t1 and t3, t3 and t5, and t5 and t7 are respectivelyapproximately 1 second, the time points t1, t3 and t5 are set as entrytime points (PTS_EP_start) in the EP_map of a video stream forpresenting a movie so as to indicate the recording positions(SPN_EP_start) in correspondence with the time points. Among the EntryPoints #1 to #4, the Entry Points #1 and #3 correspond to IDR picturesrespectively. Therefore, a value “1” is set to is_angle_change_pointsfor each of the Entry Points #1 and #3. Regarding the other EntryPoints, namely Entry Points #2 and #4, a value “0” is set tois_angle_change_point for each.

FIG. 14 illustrates PTS_EP_start and SPN_EP_start for each of the EntryPoint #1 to Entry Point #5, by a pair of EP_Low and EP_High. The EP_Lowis illustrated in the left block of the figure, and the EP_High isillustrated in the right block of the EP_High.

Among EP_Low(0) to EP_Low(Nf−1), PTS_EP_Lows of EP_Low(i) to EP_Low(i+1)respectively indicate the lower bits of t1, t3, t5 and n7. AmongEP_Low(0) to EP_Low(Nf−1), SPN_EP_Highs of EP_Low(i) to EP_Low(i+1)respectively indicate the lower bits of n1, n3, n5 and n7.

The right block in the figure illustrates EP_High (0) to EP_High (Nc−1)of the EP_map. Here, if t1, t3, t5 and t7 have a common higher bit, andn1, n3, n5 and n7 have a common higher bit, the common higher bits aredescribed in the PTS_EP_High and SPN_EP_High respectively.ref_to_EP_Low_id corresponding to the EP_High is set to indicate thefirst EP_Low (EP_Low(i)). As a result, the common higher bit of thePTS_EP_start and the SPN_EP_start are represented by the EP_High.

Among is_angle_change_point(i) to (i+3) corresponding to EP_Low(i) to(i+3), the Access Units corresponding to is_angle_change_point(i) andis_angle_change_point(i+2) are Non-IDR pictures, and therefore a value“0” is set to the is_angle_change_point.

Regarding a moving picture application for presenting a movie or thelike, once decoding is started, the subsequent pictures are sequentiallydecoded. Therefore, it is unnecessary to designate all the Access Unitsin the EP_map, and only the points that are desired to be the startingpoints of the playback should be set in the EP_map as entries. In thecase of a video stream used for representing a movie, since the intervalbetween two consecutive values of the PTS_EP_start in the EP_Map is onlyrequired to be less than 1 second. Therefore, if the interval between anAccess Unit and an adjoining Access Unit is only approximately 0.5seconds (e.g. the case of pictures existing at t2 t4 and t6), theplayback point of the Access Unit may not be indicated by thePTS_EP_start. FIG. 15 illustrates the processes through which a randomaccess to the video stream illustrated in FIG. 13.

The following description is based on an assumption that the randomaccess is performed from the In_time (=t6). In FIG. 15, t6 is notindicated by PTS_EP_start, and t5 is indicated by PTS_EP_start. TheEntry_Point corresponding to t5 is set by is_angle_change=1, whichindicates an IDR picture. Therefore, it is necessary to read the IDRpicture at the playback point of t5. This is because it is possible toprepare all the reference pictures required for decoding the accesstarget of the random access by reading the series of pictures from theIDR picture to the access target picture from the BD-ROM.

An arrow ke1 illustrated on the fourth level symbolically represents theabove-described access performed via t5. This is the overhead of therandom access.

Next, the configuration of EP_map in the case where the application_typeindicates a slide show (application_type=2 or 3). It is assumed that theslide show includes IDR pictures for which PTSs are set such that theIDR pictures are played back at a plurality of time points (t1 to t7) onthe time line. FIG. 16 illustrates the configuration of EP_map for sucha slide show. FIG. 16 illustrates the internal structure of EP_map.

In the case of a slide show, the EP_map is configured to indicate allthe pictures. Therefore, the Entry_Points #1 to #7 respectively specifythe playback points t1, t2, t3, t4, t, t6 and t7 of the IDR pictures ofthe slide show as entry times (PTS_EP_start), and associates theplayback points with the entry points (SPN_EP_start).

In this way, since all the playback points are specified by the EP_mapas the entry times, no overheads occur regardless of which among t1 tot7 is selected as the access destination. FIG. 17 illustrates a randomaccess to a point of time on a time line, in the same manner as FIG. 16.The meanings of the first to fourth levels are the same as those of FIG.16. When performing the random access to t6, among t2, t4 and t6 on thesecond level, it is unnecessary to access a preceding IDR picture toaccess the recording position corresponding to t6 (SPN=n6), because thet6 itself is indicated by the PTS_EP_start.

Since all the pictures are encoded to be IDR pictures, and the playbackpoints of all the pictures are indicated by the PTS_EP_start so as notto cause the overhead, it is possible to perform the random access in aslide show using the time information at a high speed.

In accordance with the above-described configuration of EP_map, if avalue “2” or “3” is set the application_type, it is possible to identifythat the entry points for all the pictures constituting the slide showexist in the EP_map. Therefore, the range of pieces of data to be readcan be found by referring to the entries in the EP_map, and it isunnecessary to analyze the previous and the next streams.

The above is the description of the Clip information according to thisembodiment. Note that files with the “mpls” extension are not explainedin this embodiment, but explained in the second embodiment.

This concludes the description of the recording medium according to thepresent invention. The following describes the playback device accordingto the present invention.

<Internal Structure of Playback Device>

FIG. 18 illustrates the internal structure of the playback device. Basedon the internal structure illustrated in the figure, playback devicesconsistent with the present invention are industrially manufactured. Theplayback device of the present invention is roughly composed of twoparts, one of which is a system LSI and the other is a drive device. Bymounting those parts into a device cabinet and onto a substrate, theplayback device can be manufactured industrially. The system LSI is anintegrated circuit containing various processing units for implementingthe functions of the playback device. The playback device manufacturedin the above manner is composed of a BD drive 1, an arrival time clockcounter 2, a source de-packetizer 3, a PID filter 4, a transport buffer5, a multiplexed buffer 6, a coded picture buffer 7, a video decoder 8,a decoded picture buffer 10, a video plane 11, a transport buffer 12, acoded data buffer 13, a stream graphics processor 14, an object buffer15, a composition buffer 16, a composition controller 17, a presentationgraphics plane 18, a CLUT unit 19, a transport buffer 20, a coded databuffer 21, a stream graphics processor 22, an object buffer 23, acomposition buffer 24, a composition controller 25, an interactivegraphics plane 26, a CLUT unit 27, a compositor 28, a compositor 29, aswitch 30, a network device 31, a local storage 32, an arrival timeclock counter 33, a source de-packetizer 34, a PID filter 35, a switch36, a transport buffer 37, an elementary buffer 38, an audio decoder 39,a transport buffer 40, a buffer 41, a text subtitle decoder 42, ascenario memory 43, a controller 44 and a PSR set 46. Note that theinternal structure illustrated in the figure is a decoder model based onthe MPEG T-STD model and capable of downconverting. In this figure, thepart surrounded by the dashed line is realized as a one-chip system LSI.

The BD drive 1 loads/ejects the BD-ROM and accesses the BD-ROM tosequentially reads Aligned Units each composed of 32 sectors.

The arrival time clock counter 2 generates an arrival time clock using a27 MHz crystal oscillator (27 MHz X-tal). The arrival time clock is aclock signal defining the time line on which the ATS assigned to each TSpacket is based.

Once an Aligned Unit composed of 32 sectors is read from the BD-ROM, thesource de-packetizer 3 removes the TP_extra_header from each of the 32ES-TS packets and outputs the TS packets without the headers to the PIDfilter 4. The output by the source de-packetizer 3 to the PID filter 4is performed at the timing when the time measured by the arrival timeclock counter 2 reaches the ATS shown by the TP_extra_header. Since theoutput to the PID filter 4 is carried out in accordance with the ATS,the TS packets are sequentially output to the PID filter 4 in accordancewith the time measured by the arrival time clock counter 2, regardlessof the speed at which data is read from the BD-ROM, such as 1×-speed or2×-speed.

The PID filter 4 judges, with reference to the PID attached to the TSpackets, the type of stream to which the TS packets belong is a videostream, a PG stream, or an IG stream. According to the judgment, the PIDfilter 4 outputs the TS packets to one of the transport buffer 5, thetransport buffer 12, the transport buffer 20, and transport buffer 37.

The transport buffer (TB) 5 is a buffer for temporarily storing TSpackets output from the PID filter 4, if the TS packets belong to avideo stream.

The multiplexed buffer (MB) 6 is a buffer for temporarily storing PESpackets output from the transport buffer 5, in order to later output thevideo stream to the coded picture buffer 7.

The coded picture buffer (CPB) 7 is a buffer for storing coded pictures(Non-IDR I pictures, IDR pictures, B pictures, and P pictures).

The video decoder 8 decodes individual frames contained in the videoelementary stream at every predetermined decoding time (DTS) to obtain aplurality of frames and renders the resulting picture data on thedecoded picture buffer 10.

The decoded picture buffer 10 is a buffer on which decoded picture datais rendered.

The video plane 11 is used for presenting uncompressed picture data. Aplane is a memory area of the playback device for storing a frame ofpixel value data. The video plane 11 stores picture data at theresolution of 1920×1080, and the picture data is composed of pixelvalues each expressed by 16-bit YUV values.

The transport buffer (TB) 12 is a buffer for temporarily storing TSoutput from the PID filter 4, if the TS packets belong to a PG stream.

The coded data buffer (CDB) 13 temporarily stores PES packetsconstituting a PG stream.

The stream graphics processor (SGP) 14 decodes PES packets (ODS) thatstore graphics data to obtain uncompressed bitmap expressed by indexcolors, and renders the obtained bitmap as a graphics object on theobject buffer 15.

The object buffer 15 holds the graphics object obtained by decoding anODS by the stream graphics processor 14.

The composition buffer 16 is a memory for storing control information(PCS) for rendering the graphics data.

The graphics controller 17 analyses the PCS stored in the compositionbuffer 16, and perform control based on the analysis result.

The presentation graphic plane 18 is a memory area as large as one fullscreen and stores uncompressed graphics data worth one screen. Thepresentation graphic plane 18 stores uncompressed graphics data at theresolution of 1920×1080 and the uncompressed graphics data is composedof pixel values each expressed using an 8-bit index colors. Byconverting the index colors with reference to a CLUT (Color LookupTable), the uncompressed graphics data stored on the presentationgraphics plane 18 is supplied for display.

The CLUT unit 19 converts the index colors of the uncompressed graphicsdata stored on the presentation graphic plane 18 to Y, Cr, and Cbvalues.

The transport buffer (TB) 20 is a buffer for temporarily storing TSpackets belonging to an IG stream.

The coded data buffer (CDB) 21 is a buffer for temporarily storing PESpackets constituting an IG stream.

The stream graphics processor (SGP) 22 decodes PES packets (ODS) thatstore graphics data to obtain uncompressed bitmap expressed by indexcolors, and renders the obtained bitmap as a graphics object on theobject buffer 23.

The object buffer 23 holds the graphics object obtained by decoding anODS by the stream graphics processor 22.

The composition buffer 24 is a memory for storing control information(PCS) for rendering the graphics data.

The graphics controller 25 analyses the PCS stored in the compositionbuffer 24, and perform control based on the analysis result.

The interactive graphics plane 26 is used for presenting uncompressedgraphics data obtained by decoding graphics object by the streamgraphics processor (SGP) 22. The graphics data is rendered on theinteractive graphics plane 26 at the resolution of 1920×1080, and thegraphics data is composed of pixel values each expressed using 8-bitindex colors. By converting the index colors with reference to the CLUT(Color Lookup Table), the uncompressed graphics data stored on theinteractive graphics plane 26 is supplied for presentation.

The CLUT unit 27 converts the index colors of the uncompressed graphicsdata stored on the interactive graphics plane 26 to Y, Cr, and Cbvalues.

The compositor 28 overlays the uncompressed frame data rendered on thevideo plane 11 with the uncompressed graphics object rendered on thepresentation graphic plane 18. As a result of the overlaying, thecomposite image in which text subtitles are overlaid on video isobtained.

The compositor 29 overlays the uncompressed graphics object rendered onthe interactive graphics plane 26 with the composite image (uncompressedpicture data overlaid with the uncompressed graphics object rendered onthe presentation graphic plane 18) output from the compositor 28.

The switch 30 selectively supplies the TS packets read from the BD-ROMor the TS packets read from the local storage to the transport buffer20.

The network device 31 is used to implement communications functionalityof the playback device. More specifically, the network device 31establishes TCP connection, FTF connection, and so on with a web site atan URL. The local storage 32 is a hard disk for storing contentsprovided via various types of recording media or communication media.The contents downloaded from the web site via the connection establishedby the network device 31 are stored to the local storage 32.

The source de-packetizer 34 removes the TP_extra_header from each TSpacket constituting the AV clip read from the local storage 32 andoutputs the TS packets without headers to the PID filter 35. The outputof the TS packets to the PID filter 35 is carried out at the timing whenthe time measured by the arrival time clock counter 33 reaches the ATSshown by the TP_extra_header.

The PID filter 35 switches to output the TS packets read from the localstorage 32 toward either of the IG stream decoder, the audio decoder,and the text subtitle decoder.

The switch 36 supplies toward the audio decoder 39 the TS packets readfrom the BD-ROM or from the local storage 32. The TS packets constitutethe primary audio stream. By the presence of the switch 36, the primaryaudio stream can be supplied to the audio decoder 39 from either of theBD-ROM and the local storage 32.

The transport buffer (TB) 37 stores TS packets carrying the audiostream.

The elementary buffer (EB) 38 stores the PES packets carrying the audiostream.

The audio decoder 39 decodes the PES packets output from the elementarybuffer 38 and outputs uncompressed audio data.

The transport buffer (TB) 40 stores TS packets carrying the textsubtitle stream.

The elementary buffer (EB) 41 stores PES packets carrying the secondaryaudio stream.

The text subtitle decoder 42 decodes the PES packets read into thebuffer 41 for display. This decoding is performed by expanding textstrings included in the text subtitle stream into a bitmap, using fontsindependently read from the local storage 32. The text subtitlesobtained by the decoding is to be written in the presentation graphicsplane 18.

The scenario memory 43 stores current Clip information. The current Clipinformation used herein refers to the currently processed Clipinformation from among a plurality of pieces of Clip information storedon the BD-ROM.

The controller 44 is composed of an instruction ROM and CPU and executessoftware stored on the instruction ROM to carry out overall control ofthe playback device. The control executed on the playback devicedynamically changes in response to a user event generated upon receiptof a user operation and in accordance with the values held in each PSRof the PSR set 46.

The PSR set 46 is a set of non-volatile registers provided within theplayback device. The set of registers include 64 player status registers(PSR(1)-PSR(64)) and 4,096 general-purpose registers (GPRs). The 64player status registers (PSRs) represent the current status of theplayback device, including the current playback point.

Among the 64 player status registers (PSR(1)-PSR(64)), PSR(8) is set toa value from 0-0xFFFFFFFF and indicates the current playback point(current PTM) in 45 kHz accuracy.

This concludes the description of the internal structure of the playbackdevice.

The following describes a processing procedure performed by the controlunit 44.

For playing back a video stream in the MPEG4-AVC format, the controlunit 44 controls the BD drive 1 and the video decoder 8 to perform therandom access.

One example of random access is time-search playback. The time-searchplayback is executed upon receipt of timing information from a user andplayback of a video stream is started from a playback pointcorresponding to a specific time and second indicated in the timinginformation. At the time of executing the jump playback, the controller44 converts the timing information into an Access Unit address (alsocalled “the I picture address”) stored on the BD-ROM. Then, thecontroller 44 causes the BD-ROM to be read starting from the TS packetat the thus obtained Access Unit address and causes the read TS packetsto be sequentially supplied to the decoder.

The principal part of the above-mentioned playback control is a processof deriving an Access Unit address from timing information. FIG. 19 is aflowchart of a process of converting timing information into an AccessUnit address, regarding a video stream used for presenting a movie. Inthe flowchart, the timing information denoted as In_time specifies anaccess target of the random access. In Step S1 illustrated in FIG. 19,the value of In_time is assigned to PTS_EP_start. Step S2 is tocalculate a pair of EP_High_id and EP_Low_id values indicating an entrypoint that is near the PTS_EP_start. More specifically, the EP_High_idto be calculated is an identifier specifying a nearby EP_High precedingthe In_time. On the other hand, the EP_Low_id is an identifierspecifying an EP_Low indicating a nearby temporal point following theEP_High [EP_High_id] and preceding the In_time.

In order to calculate the value of EP_High_id, the controller 44 keepsadding the time length of each PTS_EP_High included in a plurality ofEP_High values until the total Σ of the time lengths first exceeds theIn_time. The time length indicated by each PTS_EP_High is a time unitwhose most significant bits are held by the PTS_EP_High. The controller44 then identifies the k-th EP_High_id that results in the total Σ firstexceeding the In_time and determines the value obtained by (k−1) as thevalue of EP_High_id.

Similarly, to calculate the value of EP_Low_id, the controller 44 keepsadding, to the total Σ of up to the PTS_EP_High (EP_High_id), the timelength indicated by each PTS_EP_Low included in EP_Low, until theresulting total first exceeds In_time. The controller 44 then identifiesthe h-th EP_Low_id that causes the resulting total to first exceeds theIn_time, and determines the value obtained by (h−1) as the value ofEP_Low_id.

The pair of EP_High_id and EP_Low_id values specifies a nearest entrypoint preceding the In_time.

Once the EP_Low_id value is obtained, the controller 44 enters a loopcomposed of Steps S3-S5. More specifically, the controller 44 assignsthe EP_Low_id value to a variable j (Step S3) and executes the loopcomposed of the Steps S4 and S5. In each iteration of the loop, thevariable j is decremented by “1” (Step S4) and a judgment is made as towhether the is_angle_change_point (PTS_EP_Low[j].is_angle_change_point)is set to the value “1” (Step S5). The loop is repeatedly executed unitthe judgment in the Step S5 results in YES, i.e. as long as theis_angle_change_point field of each entry point is set to “0”.

That is, the loop is terminated if the entry point specified by thevariable j has the is_angle_change_point set to the value “1”. When thejudgment in the Step S5 results in YES, the controller 44 assigns thevalue of variable j to the EP_Low_id (Step S6) and calculates theEP_High[i] having the ref_to_EP_Low_id[i] that specifies an entry pointnear the EP_Low_id (Step S7). Once the values of the EP_Low_id and thevariable i are calculated, the controller 44 calculates the SPN_EP_Startusing the SPN_EP_Low[EP_Low_id]and SPN_EP_High[i] values (Step S8).Finally, the thus calculated SPN_EP_start value is converted into anAccess Unit address (Step S9).

An SPN is a serial number assigned to an individual TS packet. In orderto read a TS packet having a specific SPN, the SPN needs to be convertedinto a relative sector number. As illustrated in FIG. 4, TS packets areconverted into Aligned Units each containing 32 TS packets, and eachAligned Unit is recorded in three sectors. Thus, by dividing the SPN by32, the number of the Aligned Unit containing the Access Unit iscalculated. Then, by multiplying the Aligned Unit number by 3, thesector address of the Aligned Unit located near the SPN is calculated.The sector address calculated in the above manner is a relative sectornumber counted from the start of one AV clip. Thus, by setting the filepointer to the relative sector number, the playback apparatus reads theAV clip to supply the Access Unit to the video decoder 8.

FIG. 20 shows is a flowchart showing a processing procedure forconverting time information to an Access Unit address with respect to avideo stream used for presenting a slide show

In a slide show, all the pictures included in the video stream are IDRpictures, and the playback point of each is designated by PTS_EP_start.Therefore, it is possible to convert the In_time to the address of theIDR picture without performing Steps S3 to S7.

More specifically, in Step S1, the In_time is set to the PTS_EP_start,and in Step S2, a pair of EP_High_id and EP_Low_id that is closest tothe PTS_EP_start is obtained. Then, the SPN_EP_start is obtained fromthe SPN_EP_Low[EP_Low_id] and SPN_EP_High[EP_High_id] (Step S8) toobtain the Access Unit address (Step S9). This means that the procedurefor obtaining the Access Unit address is greatly simplified.

Here, also in the case of playing back a slideshow, the procedure ofStep S1 in FIG. 19 is performed. In other words, to obtain theEP_High_id, the control unit 44 adds the durations indicated by eachPTS_EP_High of a plurality of EP_Highs, and judges how many EP_High_idsare added when the total Σ of the durations becomes larger than theIn_time. Here, if the total Σ becomes larger than the In_time when the1st to kth EP_High_ids are added, a value “k−1” is considered asEP_High_id.

To obtain the EP_Low_id, the control unit 44 adds the durationsindicated by each PTS_EP_Low of a plurality of EP_Lows to the total Σ asthe total up to the PTS_EP_High(EP_High_id), and judges how manyEP_Low_ids are added when the total Σ of the durations becomes largerthan the In_time. Here, if the total Σ becomes larger than the In_timewhen the 1st to hth EP_Low_ids are added, a value “h−1” is considered asEP_Low_id.

Based on the pair of the EP_High_id and the EP_Low_id obtained in theabove-described manner, the Entry Point that is the same as the In_timeor the closest to the In_time.

In this way, if there is any PTS_EP_start that is the same as theIn_time, it is possible to perform reading and playback of the picturedata from, among the plurality of PTS_EP_starts in the EP_map, theSPN_EP_start corresponding to the PTS_EP_start that is the same as theIn_time.

Among the plurality of PTS_EP_starts in the EP_map, if there is noPTS_EP_start that is the same as the In_time, reading and playback ofpicture data from the SPN_EP_start corresponding to the PTS_EP_startclosest to the In_time is performed.

As described above, according to this embodiment, in a slide show thatdoes not display the previous and the next picture in accordance withthe user's instruction, and in accordance with skip operation and so on,displays still pictures regardless of the order of the pictures, all thestill pictures are IDR pictures indicated by the EP_map, and it isunnecessary to analyzes the streams.

Also, each Access Unit (Non-IDR I picture, IDR picture) is designated byEnrty_Point in EP_map. Therefore, it is possible to directly access onlynecessary Access Units to read the Access Units and supply the AccessUnits to the decoder. This means that the access efficiency is high andthe time required for displaying the data is short.

Note that a flag for ensuring that the entry addresses of all the piecesof the picture data constituting the video stream may be recorded in aEP_map or navigation information relating thereto.

Second Embodiment

The second embodiment relates to improvement of setting of chapters on atime line of a slide show.

The following describes information for defining the chapters.

The information for defining the chapters is PlayList information, whichexists in files with the “mpls” extension. The following describes thePlayList Information.

<PlayList Information>

Next is a description of PlayList information. Files with the “mpls”extension (00001.mpls, 00002.mpls, 00003.mpls, . . . ) are files storingPlayList information. PlayList information defines a playback pathcalled a PlayList with reference to an AVClip. FIG. 21 shows a structureof the PlayList information, which as shown in the left side of thefigure includes a plurality of pieces of PlayItem Information. APlayItem is a playback period that is defined by specifying an In_timeand an Out_time on at least one AVClip time-axis. Arranging a pluralityof pieces of PlayItem information defines a PlayList (PL) that iscomposed of a plurality of playback periods. A dashed line hs1 in thefigure indicates a detailed structure of the PlayItem information. Asshown in the figure, the PlayItem information is composed of“Clip_information_file_name” which indicates a corresponding piece ofClip information, “Clip_codec_identifier” which indicates an encodingmethod of a corresponding AVClip, “In_time” which indicates a time atwhich playback of the AVClip is to be started, “Out_time” whichindicates a time at which playback of the AVClip is to be ended,“Still_mode”, and “Still_time”. FIG. 22 shows a relation between the AVClip and the PlayList information. The first level illustrates the timeline of the AV Clip. The second level illustrates the time line of thePlayList information (Hereinafter called “the PL time line”). ThePlayList information includes three pieces of PlayList information,namely PlayItem Info #1, PlayItem Info #2 and PlayItem Info #3. Thepairs of In_time and Out_time in the respective pieces of PlayItem Info#1, #2 and #3 define three playback sections. When aligning the threeplayback sections, a time line that is different from the AV clip timeline is defined. This time line is the PL time line illustrated on thesecond level. As described herein, by defining PlayItem information, adifferent time line from the AV clip time line is defined.

It is Still_mode and Still_time that are characteristic among theinformation elements that constitute this PlayList information.

“Still_mode” indicates whether to still-display a last piece of picturedata when playing back picture data from the In_time to the Out_time. Ifconfigured to “00”, the Still_mode indicates that still-display is notto be continued. If configured to “01”, the Still_mode indicates thatstill-display is to be continued for a limited time period. If theStill_mode is configured to “01”, the length of still-display isconfigured to Still_time. If configured to “02”, the Still_modeindicates continuation of still-display for an unlimited time period. Anexplicit operation from a user cancels the display in the case ofstill-display for an unlimited time period.

If the Still_mode is configured to 01, the length of time still-displayis to be continued is indicated by “Still_time” in units of seconds.

This completes the description of PlayItem information pertaining to thepresent embodiment. Next is a description of PL Mark information.

FIG. 23 shows an internal structure of each of a plurality of pieces ofPLMark information, which is included in PlayList information accordingto the second embodiment. PLMark information (PLMark( )) shown in FIG.23 is information that specifies an arbitrary period on a PL time-axisas chapter points. As shown by a lead line pm1 in FIG. 23, the PLMarkinformation includes “ref_to_PlayItem_Id”, and “mark_time_stamp”. FIG.24 illustrates definitions of chapters according to the PLMarkinformation. In this figure, the first level illustrates the time lineof the AV Clip, and the second level illustrates the PL time line.Arrows pk1 and pk2 respectively indicate designations of PlayItem(ref_to_PlayItem_Id) and a point of time (mark_time_stamp). Thesedesignations define the three chapters (Chapters #1, #2 and #3) on thePL time line. This concludes the description of PLMark.

FIG. 25 shows specification of a slideshow by PlayList information. Thesecond level in the figure indicates PlayItem information. This secondlevel is composed of six pieces of PlayItem information #1 to #6. Arrowsyt1, yt2, yt3, yt4, yt5 and yt6 symbolically indicate specification byIn_times and Out_times in the PlayItem information, and arrows st1, st2,st3, st4, st5 and st6 symbolically indicate specification byStill_times. As is apparent from these arrows, PlayItem information isconfigured so as to specify individual pieces of picture data in thevideo stream. Also, the Still_times are configured so as to indicate aperiod until display of a subsequent piece of picture data. In this way,the individual pieces of picture data that constitute the slideshow arespecified by a respective one of the six pieces of PlayItem informationas playback start points and playback end points.

The first level in FIG. 25 indicates PLMark information. In this firstlevel are six pieces of PLMark information #1 to #6. Arrows kt1, kt2,kt3, kt4, kt5 and kt6 indicate specification by ref_to_PlayItem_Id ofthe PLMark information. As is apparent from these arrows, eachref_to_PlayItem_Id of the PLMark information specifies a piece ofPlayItem information.

Next, playback in accordance with PlayItem information is described.Each piece of picture data included in a slide show is pointed by thePlayItem information and the PLMark information. Therefore, the controlunit 44 converts the In_time and the Out_time of the PlayIteminformation to the SPN of the AV Clip, using the EP_map, and suppliesthe picture data existing in the SPN to the decoder. As a result, thepicture data specified by the In_time and the Out_time of the PlayIteminformation is displayed. After that, the display of the picture is keptfor the duration indicated by the Still_Time. The control unit 44 ofthis embodiment plays back a slide show by repeating the above-describedprocedure for all the pieces of PlayItem Information.

The chapter search function specifies from among the pieces of PlayIteminformation, a piece of PlayItem information corresponding toref_to_PlayItem_Id described in the PLMark information, and performs arandom access in the AVClip defined by the specified piece of PlayIteminformation from a position that is indicated in mark_time_stampdescribed in the PLMark information. At this time, the control unit 44specifies from among a plurality of Entry Points, the Entry Point havinga PTS_EP_start closest to mark_time_stamp described in the PLMarkinformation, and causes playback to be performed from the Access Unitaddress corresponding to SPN_EP_start of the specified Entry Point.

The chapter skip specifies a piece of PLMark information that defines achapter directly before or directly after the chapter at the currentplayback position, and performs a chapter search to the chapter definedby the specified PLMark information. As described above, the picturespecified by the mark_time_stamp of the PLMark information is encoded tobe an IDR picture, and the SPN_EP_start of the Entry Point whoseis_angle_change_point is “1” indicates the playback time of the IDRpicture. Therefore, it is possible to supply the IDR pictures to thevideo decoder 8 by reading the pictures succeeding the picture at theposition indicated by the SPN_EP_start of the Entry Point.

The following describes a chapter search processing procedure and achapter skip processing procedure. FIG. 26 is a flowchart showing achapter search processing procedure.

In this flowchart, the control unit 9 first waits for selection of achapter from a chapter menu (step S124), and, when the chapter selectionis performed, sets the PLMark information pertaining to the selectedchapter as the current PlayListMark (step S125). In step S126, a PIdescribed in ref_to_PlayItem_Id of the current PlayListMark is set toPlayItem#x, and a piece of Clip information indicated byClip_information_file_name of the PlayItem#x is read in step S127. Instep S128, mark_time_stamp of the current PlayListMark is converted toan Access Unit address u using the EP_map of the current Clipinformation. Here, the picture indicated by the mark_time_stamp of thePLMark information is indicated by the Entry Point whoseis_angle_change_point is “1”. Accordingly, the Access Unit address uindicates the address of the IDR picture.

On the other hand, Out_time of the PlayItem#x is converted to an AccessUnit address v in step S129 using the EP_map of the current Clipinformation. The decoder is instructed in step S130 to output frommark_time_stamp of the current PlayListMark to Out_time of thePlayItem#x. This completes the chapter search processing procedure. Nextis a description of a chapter skip processing procedure. FIG. 27 is aflowchart showing the chapter skip processing procedure.

In step S131, the control unit 9 waits for an operation of a SkipNextkey or a SkipBack key of the remote control. If the operation isperformed, step S132 is executed. In step S132, the control unit 9judges whether the SkipNext key or the SkipBack key was pressed, and adirection flag is set to −1 in step S133 if the SkipBack key waspressed, and the direction flag is set to +1 in step S134 if theSkipNext key was pressed.

In step 135, a current PI and a current PTM are converted, and a currentPLMark is specified. In step S136, a number of the current PLMark is setto the current PLMark number plus a value of the direction flag. If theSkipNext key was pressed, the PLMark is incremented since the directionflag has been set to +1. If the SkipBack key was pressed, the currentPLMark is decremented since the direction flag has been set to −1. Ifthe PLMark information is set in this way, reading of TS packets isperformed by executing the processing procedure of steps 126 to S130,similarly to FIG. 25.

This concludes the description of the processing procedure performed bythe playback device to perform playback in accordance with the PLMarkinformation.

Here, the following describes the case of setting the PLMark for thevideo stream shown in FIG. 25. The pictures that can be played back inthe slide sow are specified by the six PLMarks on the first level,namely PLMark#1 to PLMark#1. Therefore, the still pictures located atthe time points t1, t2, t3, t4, t5 and t6 can be targets of the chaptersearch and the chapter skip.

Also, each of the time points t1, t2, t3, t4, t5 and t6 is specified asPTS_EP_start in the EP_map on the fifth level. Therefore, it is possibleto perform random access directly to a desired chapter by the chaptersearch and the chapter skip, without accessing the preceding IDRpicture. To read a desired picture, it is possible to perform thechapter search and the chapter skip without accessing the preceding IDRpicture. Therefore, it is possible to perform the chapter search and thechapter skip highly efficiently even in the case of a slide show.

As described above, according to this embodiment, it is possible toperform the chapter search and the chapter skip highly efficiently evenin the case of a slide show.

Third Embodiment

This embodiment is an application of the first embodiment and the secondembodiment, and relates to an introduction of an interactive controlinto the slide show. To introduce such an interactive control, IG streamis multiplexed to form AV Clip, as well as the video stream and theaudio stream shown in FIG. 3. FIG. 28 illustrates the structure of AVClip according to the third embodiment. In this figure, an AV Clip (themiddle level) is structured by converting a video stream that includes aplurality of video frames (pictures pj1, pj2, pj3) and an audio streamthat includes a plurality of audio frames (the upper first level) intoPES packet strings (the upper second level), and further converting thePES packet strings into TS packets (the upper third level), and alsoconverting an interactive graphics stream (IG stream, on the lowersecond level) into TS packets (the lower third level), and multiplexingthe TS packets. FIG. 29 illustrates the internal structure of an IGstream.

An interactive graphics stream includes an ICS (Interactive CompositionSegment), a PDS (Palette Definition Segment), an ODS (Object DefinitionSegment) and an END (END of Display Set Segment).

The ODS (Object Definition Segment) is graphics data that defines thedesign of a graphic when rendering a button.

The PDS (Palette Definition Segment) is a function segment that definescolor when rendering the graphics data.

The ICS (Interactive Composition Segment) is a function segment thatdefines interactive control which changes button states according touser operation.

FIG. 29B shows an internal structure of the ICS. The ICS is composed ofpieces of button information. The pieces of button informationcorrespond respectively to individual buttons of an interactive controlscreen. Specifically, the ICS is composed of “neighbor_info” which showsa button to move the focus to if the focus is on a corresponding buttonand then a move key is pressed, “state_info” that shows which ODS is tobe used to display states such as a normal state and selected state of acorresponding button, and “navigation commands” to cause the playbackapparatus to perform execution when selection of a corresponding buttonis confirmed.

The data structure of the above-described IG stream is a summary ofcontent included in the following publicly known document. More detailedtechnical content can be found in the following document.

International Publication No. WO 2004/077826

The following describes a specific example of an ICS.

Here, the ICS has state_info, neighbor_info and a navigation commandconfigured as shown in FIG. 30. FIG. 30 shows an exemplary ICS thatspecifies interactive control of the slideshow.

1. State_Info

If a button (“top” button) corresponding to Button_info(0) is in anormal state, state_info of Button_info(0) is specified such that atriangular graphic with “top” is rendered on the screen. Also, thestate_info is specified such that the triangular graphic with “top” isrendered in an emphasized state if focus is on the “top” button (in aselected state). As a result of this specification, the “top” button canbe handled as a button for skipping to the first still image.

If a button (“+1” button) corresponding to Button_info(1) is in thenormal state, state_info of Button_info(1) is specified such that atriangular graphic with “+1” is rendered on the screen. Also, thestate_info of Button_info(1) is specified such that the triangulargraphic with “+1” is rendered in an emphasized state if the “+1” buttonis in the selected state. As a result of this specification, the “+1”button can be handled as a button for skipping to the next still image.

If a button (“−1” button) corresponding to Button_info(2) is in thenormal state, state_info of Button_info(2) is specified such that atriangular graphic with “−1” is rendered on the screen. Also, thestate_info of Button_info(2) is specified such that the triangulargraphic with “−1” is rendered in an emphasized state if the “−1” buttonis in the selected state. As a result of this specification, the “−1”button can be handled as a button for skipping to the previous stillimage.

If a button (“+10” button) corresponding to Button_info(3) is in thenormal state, state_info of Button_info(3) is specified such that atriangular graphic with “+10” is rendered on the screen. Also, thestate_info of Button_info(3) is specified such that the triangulargraphic with “+10” is rendered in an emphasized state if the “+10”button is in the selected state. As a result of this specification, the“+10” button can be handled as a button for skipping to the 10th stillimage from the still image currently displayed.

If a button (“−10” button) corresponding to Button_info(4) is in thenormal state, state_info of Button_info(4) is specified such that atriangular graphic with “−10” is rendered on the screen. Also, thestate_info of Button_info(4) is specified such that the triangulargraphic with “−10” is rendered in an emphasized state if the “−10”button is in the selected state. As a result of this specification, the“−10” button can be handled as a button for skipping back 10 frames.

As shown in FIG. 31A, the graphics specified by state_info of thebuttons from the “top” button to the “−10” button are included in theODSs of the IG stream. State_info is configured with this kind ofcontent, and a PTS indicates a point tx on a time-axis at which an xthpicture is to be displayed, as shown in FIG. 31B. As a result of this, amenu as shown in FIG. 31C is displayed in combination with the xth stillimage when the playback point of the video stream reaches the point tx.

2. Neighbor_Info of an ICS

The following references neighbor_info of each object B in FIG. 30.

Neighbor_info of Button_info(0) is specified such that the focus ismoved to the “−1” button having the number “2” when a left key ispressed, and to the “+1” button having the number “1” when a right keyis pressed.

Neighbor_info of Button_info(1) is specified such that the focus ismoved to the “top” button having the number “0” when an up key ispressed, to the “−1” button having the number “2” when the left key ispressed, and to the “+10” button having the number “3” when the rightkey is pressed.

Neighbor_info of Button_info(2) is specified such that the focus ismoved to the “−10” button having the number “4” when the left key ispressed, to the “+1” button having the number “1” when the right key ispressed, and to the “top” button having the number “0” when the up keyis pressed.

Neighbor_info of Button_info(3) is specified such that the focus ismoved to the “+1” button having the number “1” when the left key ispressed.

Neighbor_info of Button_info(4) is specified such that the focus ismoved to the “−1” button having the number “2” when the right key ispressed.

The above specifications of neighbor_info enable the realization ofstate transitions as shown in FIG. 32. FIG. 32 shows state transitionsof a menu displayed in the slideshow.

Specifically, if the left key is pressed while the focus is on the “+1”button, the focus can be moved to the “−1” button (hh1).

If the right key is pressed while the focus is on the “+1” button, thefocus can be moved to the “+10” button (hh2). Furthermore, if the leftkey is pressed while the focus is on the “+10” button, the focus can bereturned to the “+1” button (hh4). If the up key is pressed while thefocus is on the “+1” button, the focus can be moved to the “top” button(hh3).

As mentioned above, the “top” button, “+1” button, “−1” button, “+10”button and “−10” button are respectively for skipping to the beginning,next picture, previous picture, 10 pictures ahead and 10 picturesbehind. Given that the focus moves in accordance with a user press ofthe up, down, left and right keys when these buttons are displayed, theuser can make an arbitrary one of the “+1” to “−10” buttons a selectiontarget.

3. Navigation Commands of an ICS

The navigation command of Button_info(0) is specified such that JmpPLMark(1) is executed if a determination operation is performed on the“top” button.

The navigation command of Button_info(1) is specified such that JmpPLMark(x+1) is executed if the determination operation is performed onthe “+1” button.

The navigation command of Button_info(2) is specified such that JmpPLMark(x−1) is executed if the determination operation is performed onthe “−1” button.

The navigation command of Button_info(3) is specified such that JmpPLMark(x+10) is executed if the determination operation is performed onthe “+10” button.

These navigation commands designate a PLMark as a branch destination.The number value inside the parentheses pertaining to the PLMarkdesignates a picture as the branch destination. In other words,PLMark(1) is a PLMark indicating the first picture. PLMark(x+1) is aPLMark indicating the picture corresponding to x−1. PLMark(x+10) is aPLMark indicating a picture corresponding to x+10. PLMark(x−10) is aPLMark indicating a picture corresponding to x−10.

The navigation commands of the button information designate PLMark(1),PLMark(x+1), PLMark(x−1), PLMark(x+10), PLMark(x−10) as branchdestinations, thereby enabling random access to, with respect to the xthstill picture, the first still picture, x+1th still picture, x−1th stillpicture, x+10th still picture, and x−10th still picture when a button isselected.

Given that the focus can be moved to an arbitrary button as a result ofthe focus movement shown in FIG. 30, the user can perform thedetermination operation while the focus is on any of the buttons tocause the playback apparatus to execute the navigation commandcorresponding to the selected button, thereby enabling the execution ofthe branching as shown in FIG. 32. FIG. 32 shows branching as a resultof navigation commands of the slideshow. The first level of this figureshows a plurality of pictures that constitute the slideshow, andbranches to these pictures. The second level is the time-axis of theslideshow, the third level is an entry map configured with respect tothe picture string of the second level, and the fourth level shows a TSpacket string on the BD-ROM.

Arrows of the first level in the figure symbolically show branchesresulting from the navigation commands (JmpPLMark(1), JmpPLMark(x+1),JmpPLMark(x−1), JmpPLMark(x+10), JmpPLMark(x−10)) shown in FIG. 30. As aresult of these branches, the first still picture, the next stillpicture, the previous still picture, 10th still picture ahead, or 10thstill picture behind is played back. These branches are based on thenavigation commands shown in FIG. 30, thereby enabling an arbitrarystill picture to be played back by user operation.

Here, if each of the playback points of the first still picture, thenext still picture, the previous still picture, the 10th still pictureahead, and the 10th still picture behind is specified as PTS_EP_start inEP_map, it is possible to perform random access to a desired accesspoint without analyzing the stream. Since it is possible to perform aninteractive playback operation using navigation commands to read adesired picture, the interactive playback operation becomes highlyefficient.

Remarks

The above description by no means shows the implementation of allconfigurations of the present invention. Implementation of the presentinvention is still possible according to implementation ofconfigurations that carry out the following modifications (A), (B), (C,(D), . . . . The inventions pertaining to the claims of the presentapplication range from expanded disclosure to generalized disclosure ofthe plurality of embodiments disclosed above and the modifiedconfigurations thereof. The degree of expansion or generalization isbased on the particular characteristics of technical standards in thetechnical field of the present invention at the time of the application.

(A) Although a recording medium pertaining to the present invention isimplemented as a BD-ROM in all of the embodiments, the recording mediumof the present invention is characterized by the recorded EP_map, andthis characteristic is not dependent on the physical properties of aBD-ROM. Any form of recording media is applicable as long as thereexists the capacity to record an EP_map. For example, optical disks suchas DVD-ROM, DVD-RAM, DVD-RW, DVD-R, DVD+RW, DVD+R, CD-R, CD-RW and thelike, and optical-magnetic disks such as PD, MO and the like areapplicable. Semiconductor cards such as a CompactFlash card (registeredtrademark), a SmartMedia card, a Memory Stick, a MultiMedia card, aPCM-CIA card and the like are also applicable, as well as (i) magneticrecording disks such as a flexible disk, SuperDisk, Zip, Clik! and thelike, and (ii) removable hard disk drives such as ORB, Jaz, SparQ,SyJet, EZFley, microdrive and the like. Furthermore, the recordingmedium may also be a built-in hard disk.

(B) Although the playback apparatuses in all of the embodiments outputAVClips recorded on a BD-ROM to a TV after decoding, the playbackapparatus may be structured from only a BD-ROM drive, and the TV may beequipped with all of the other elements. In this case, the playbackapparatus and the TV can be incorporated into a home network connectedusing IEEE1394. Also, although the playback apparatuses in theembodiments are of a type used after connecting to a television,integral display-playback apparatuses are also applicable. Furthermore,the playback apparatus may be only a system LSI (integrated circuit)that performs essential parts of the processing in the playbackapparatuses of the embodiments.

(C) Because of the information processing by a computer program shown ineach of the flowcharts being realized specifically using hardwareresources, a computer program showing the processing procedures in theflowchart forms an invention in its own right. Although all of theembodiments show embodiments that relate to the implementation ofcomputer programs pertaining to the present invention in an incorporatedform in the playback apparatuses, the computer programs shown in thefirst to third embodiments may be implemented in their own right,separate from the playback apparatuses. The implementation of thecomputer programs in their own right includes acts that involve: (1)production of the programs, (2) transference of the programs, eithergratuitous or otherwise, (3) lending of the programs, (4) importing ofthe programs, (5) providing the programs publicly via bi-directionalelectronic communications circuits, and (6) approaching the general userabout transfer, rental and the like by means of show-window displays,catalogue solicitation, pamphlet distribution, and so forth.

(D) Although digital streams in the embodiments are AVClips complyingwith a BD-ROM standard, the digital streams may be VOBs (Video Objects)complying with a DVD-Video standard or a DVD-Video Recording standard.VOBs are program streams compliant with ISO/IEC13818-1 obtained bymultiplexing video and audio streams. Also, video streams in AVClips maybe MPEG-4 format, WMV format, or the like. Furthermore, audio streamsmay be a Linear-PCM format, Dolby-AC3 format, MP3 format, MPEG-AACformat, or dts format.

(E) In the first embodiment, the slide show is described as the TS forTimebased SlidShow. However, the slide show may AVClip used for TS forMainPath of the Browsable SlideShow, or AVClip used for SubPath of theBrowsable SlideShow. In other words, it is acceptable to set the EP_mapin the Clip information corresponding to the AV Clip used for TS forMainPath of the Browsable SlideShow, to indicate the playback point andthe recording position of each picture.

(F) Each of the embodiments above is described based on the MPEG4-AVC(also referred as H.264 or JVT). However, the MPEG2 video stream may beused. Also, any other picture format (VC-1) is easily applicable as longas the picture can be decoded independently.

INDUSTRIAL APPLICABILITY

A recording medium and a playback apparatus of the present invention maybe used personally as in a home theater system. However, the recordingmedium and the playback apparatus of the present invention may beproduced and used in the industrial production field since the internalstructure thereof is disclosed in the embodiments described above, andit is apparent that the playback apparatus of the present invention willbe mass-produced. For this reason, the recording medium and the playbackapparatus of the present invention have industrial applicability.

1. A non-transitory recording medium having recorded thereon a video stream and stream management information, wherein the video stream includes a plurality of pieces of picture data, each picture data piece in the video stream has a variable code length and has been converted into an access unit, the access unit having a plurality of Network Abstraction Layer (NAL) units, among the plurality of NAL units, a first NAL unit includes an access unit delimiter, the stream management information includes an entry map and a flag that indicates one of application types, the entry map indicates an entry address of each piece of picture data in correspondence with a playback start time thereof, the application types include a movie and a time-based slideshow, if a value indicating the time-based slideshow has been set to the flag, all the pieces of picture data are respectively pointed to by entries included in the entry map, if a value indicating the movie has been set to the flag, intra pictures among the pieces of picture data are respectively pointed to by the entries included in the entry map, the intra pictures each located at a head of a GOP, a rate of entries in the entry map for pointing to the picture data in the video stream is higher when the value indicating the time-based slideshow has been set to the flag than when the value indicating the movie has been set to the flag, the rate of entries being a number of entries per frames in the video stream, and when the value indicating the time-based slideshow has been set to the flag, all pictures constituting the time-based slideshow in the video stream are encoded as IDR pictures.
 2. The non-transitory recording medium according to claim 1, wherein: the video stream is in an MPEG4-AVC format and is recorded in a form of TS packets having a fixed length, and among the TS packets, a TS packet including an access unit delimiter does not include an end portion of a picture data piece that is immediately before the TS packet in the video stream.
 3. A playback device that reads stream management information from a recording medium and plays back, based on the stream management information, a video stream recorded on the recording medium, wherein the video stream includes a plurality of pieces of picture data, each picture data piece in the video stream has a variable code length and has been converted into an access unit, the access unit having a plurality of Network Abstraction Layer (NAL) units, among the plurality of NAL units, a first NAL unit includes an access unit delimiter, the stream management information includes an entry map and a flag that indicates one of application types, the entry map indicates an entry address of each piece of picture data, which is included in the video stream, in correspondence with a playback start time thereof, the application types include a movie and a time-based slideshow, if a value indicating the time-based slideshow has been set to the flag, all the pieces of picture data are respectively pointed to by entries included in the entry map, if a value indicating the movie has been set to the flag, intra pictures among the pieces of picture data are respectively pointed to by the entries included in the entry map, the intra pictures each located at a head of a GOP, a rate of entries in the entry map for pointing to the picture data in the video stream is higher when the value indicating the time-based slideshow has been set to the flag than when the value indicating the movie has been set to the flag, the rate of entries being a number of entries per frames in the video stream, and when the value indicating the time-based slideshow has been set to the flag, all pictures constituting the time-based slideshow in the video stream are encoded as IDR pictures, and the playback device comprises: a read unit operable to read the pieces of picture data from the recording medium; a playback unit operable to play back the pieces of picture data by decoding each piece of the picture data; and a control unit operable, if the value indicating the time-based slideshow has been set to the flag, to control the read unit and the playback unit to start the playback or change a start position of the playback based on a designation of a playback start time, with reference to the entry map.
 4. A recording method comprising: generating volume data; and recording the volume data on a recording medium; wherein: the volume data includes a video stream and stream management information, the video stream includes a plurality of pieces of picture data, each picture data piece in the video stream has a variable code length and has been converted into an access unit, the access unit having a plurality of Network Abstraction Layer (NAL) units, among the plurality of NAL units, a first NAL unit includes an access unit delimiter, the stream management information includes an entry map and a flag that indicates one of application types, the entry map indicates an entry address of each piece of picture data in correspondence with a playback start time thereof, the application types include a movie and a time-based slideshow, if a value indicating the time-based slideshow has been set to the flag, all the pieces of picture data are respectively pointed to by entries included in the entry map, if a value indicating the movie has been set to the flag, intra pictures among the pieces of picture data are respectively pointed to by the entries included in the entry map, the intra pictures each located at a head of a GOP, a rate of entries in the entry map for pointing to the picture data in the video stream is higher when the value indicating the time-based slideshow has been set to the flag than when the value indicating the movie has been set to the flag, the rate of entries being a number of entries per frames in the video stream, and when the value indicating the time-based slideshow has been set to the flag, all pictures constituting the time-based slideshow in the video stream are encoded as IDR pictures.
 5. A playback method for reading stream management information from a recording medium and playing back, based on the stream management information, a video stream recorded on the recording medium, wherein the video stream includes a plurality of pieces of picture data, each picture data piece in the video stream has a variable code length and has been converted into an access unit, the access unit having a plurality of Network Abstraction Layer (NAL) units, among the plurality of NAL units, a first NAL unit includes an access unit delimiter, the stream management information includes an entry map and a flag that indicate one of application types, the entry map indicates an entry address of each piece of picture data, which is included in the video stream, in correspondence with a playback start time thereof, the application types include a movie and a time-based slideshow, if a value indicating the time-based slideshow has been set to the flag, all the pieces of picture data are respectively pointed to by entries included in the entry map, if a value indicating the movie has been set to the flag, intra pictures among the pieces of picture data are respectively pointed to by the entries included in the entry map, the intra pictures each located at a head of a GOP, a rate of entries in the entry map for pointing to the picture data in the video stream is higher when the value indicating the time-based slideshow has been set to the flag than when the value indicating the movie has been set to the flag, the rate of entries being a number of entries per frames in the video stream, and when the value indicating the time-based slideshow has been set to the flag, all pictures constituting the time-based slideshow in the video stream are encoded as IDR pictures, and the playback method comprises: reading the pieces of picture data from the recording medium; playing back the pieces of picture data by decoding each piece of the picture data; and if the value indicating the time-based slideshow has been set to the flag, controlling the reading and the playing back to start the playback or change a start position of the playback based on a designation of a playback start time, with reference to the entry map.
 6. A computer-executable program recorded on a non-transitory recording medium for causing a computer to perform processing for reading stream management information from a recording medium and playing back, based on the stream management information, a video stream recorded on the recording medium, wherein the video stream includes a plurality of pieces of picture data, each picture data piece in the video stream has a variable code length and has been converted into an access unit, the access unit having a plurality of Network Abstraction Layer (NAL) units, among the plurality of NAL units, a first NAL unit includes an access unit delimiter, the stream management information includes an entry map and a flag that indicate one of application types, the entry map indicates an entry address of each piece of picture data, which is included in the video stream, in correspondence with a playback start time thereof, the application types include a movie and a time-based slideshow, if a value indicating the time-based slideshow has been set to the flag, all the pieces of picture data are respectively pointed to by entries included in the entry map, if a value indicating the movie has been set to the flag, intra pictures among the pieces of picture data are respectively pointed to by the entries included in the entry map, the intra pictures each located at a head of a GOP, a rate of entries in the entry map for pointing to the picture data in the video stream is higher when the value indicating the time-based slideshow has been set to the flag than when the value indicating the movie has been set to the flag, the rate of entries being a number of entries per frames in the video stream, and when the value indicating the time-based slideshow has been set to the flag, all pictures constituting the time-based slideshow in the video stream are encoded as IDR pictures, and the processing comprises: reading the pieces of picture data from the recording medium; playing back the pieces of picture data by decoding each piece of the picture data; and if the value indicating the time-based slideshow has been set to the flag, controlling the reading and the playing back to start the playback or change a start position of the playback based on a designation of a playback start time, with reference to the entry map. 